Resistance element for rail heaters



NOV. 13, 1934. w, H GREENFlELD 1,980,582

RESISTANCE ELEMENT FOR RAIL HEATERS Original Filed Oct. 7, 1930 Zuelzov WILLIA H. GREENFIELD, @M

Patented Nov. 13, 1934 1,980,582 RESISTANCE ELEMENT FOR RAIL HEA'IERS William H. Greenlield, Philadelphia, Pa. Original application October 7, 1930, Serial No.

2 Claims.

This invention relates to rail heating devices and more particularly to electric heaters which are operative to prevent the formation or accumulation of sleet, snow and ice around rail 6 switches and derail points and on conductor rails employed on electrified railroads to deliver power to cars or trains. Primarily the invention consists of heat radiating units positioned at said switch or derail points or at in- 10 tervals kspaced along said conductor rails for supplying heat to the track, these units being electrically operated from local or distant stations as may be desired.

This application is a division of my pending application, Serial No. 486,897, filed October 7, 1930, disclosing my invention having as one of its principal objects the provision of means for applying heat tovpredetermined zones of a railway track by direct radiation from a high resistance heating element, this element being in the form of an electric resistor which is adapted to raise the temperature of the rail in the zone in which the element is located to a degree sufliciently high to prevent the formation of sleet, snow or ice in said zone.

A further object of the invention is to provide a resistance element which is so designed as to effectively concentrate the heat in the desired zone whereby the loss in heat transmission from said element to the rail is reduced to a veritable minimum.

Still another object of the present invention is the provision of an electrical resistor unit which is capable of developing a high degree of heat overa long period of use and which is so designed and constructed as to withstand the vibrations and shocks to which it is subjected while in use.

A still further object is the design and provi- 40 sion of a resistance unit which is readily mounted within the rail heating unit and which may be readily removed therefrom at will for periodic inspection and repair.

Other objects of the invention, such as those relating generally to simplicity in design, economies of manufacture and efciency and durability in use and specifically to details of construction will appear more fully hereinafter.

The invention consists substantially in the combination, construction, location and relative arrangement of parts, all as will be described more fully hereinafter, as shown in the accompanying drawing and as finally pointed out in the appended claims. In the accompany- Divided and 1932, Serial No. 626,573

this application July 30,

(Cl. 21S- 19) ing drawing wherein have been illustrated preferred embodiments of the inventionz- Figure 1 is a vertical cross-sectional view of a. rail equipped with a heating unit including a resistance element constructed in accordance with and embodying the principles of the present invention; f

Figure 2 is a perspective view showing the interior of the unit; v

Figure 3 is a longitudinal sectional one form of resistance element;

Figure 4 is a cross-sectional view taken on the line 4 4 ofFigure 3;

Figure 5 is a longitudinal sectional view of a modied form of resistance element; and

Figure 6 is a cross-sectional view taken on line 6-6 of Figure 5.

Referring now to the drawing and more particularly to Figures 1 and 2 thereof, it will be observed that the rail heating unit, designated generally by the reference numeral 10, is adapted to be mounted in position within the angle formed between the base flange and web of a main rail R. It will be understood that this rail 11 may be a portion of an ordinarytrack switch or frog or a portion of a conductor rail for supplying electric power to electrically driven cars or trains. It will futher be understood that the rail heating units 10 arer designed to be located at spaced intervals along the track, particularly at points where the formation or the accumulation of ice, sleet or snow would entail more or less serious consequences.

The heating unit 10 essentially comprises an electrical resistance element 11 which is supported upon the inner surface of a main casing or housing 12. As appears quite clearly in Figures 1 and 2 this housing 12, which is preferably in the form of a sheet metal stamping, is provided with an inclined wall or plate 13 the upper and lower longitudinally extending edges of which are flanged, as at 14 and 15. The sides edges of the housing plate 13 are respectively inturned to provide a pair of substantially parallel, triangularly shaped side walls 16. These triangular side walls 16 are so shaped that when the bottom edges 1'7 thereof rest upon the upper surface of the base ilange of the rail the vertical edges 18 thereof will abut the web of the rail. The main back plate 13 of the sheet metal housing lies in a plane substantially subtending the `free edges of the triangular side walls thereof, as most clearly appears in Figure 2. When the housing is applied to the rail an enclosed space or chamber is formed therebeview of ,welA

tween, this space being bounded at its outer side by the inclined back plate 13, at its sides by the triangular side walls 16, at its bottom by the base flange of the rail and at its inner side by the web of the rail. The heating element 11 is supported upon the inclined back plate in the manner lto be described more fully hereinafter and in spaced relation with respect to the 'enclosed portions of the rail.

1n order to most effectively concentratevthe heat and to direct it against the rail with a minimum loss in heat transmission the main back plate 13 of the housing or casing is pro- Videdw'ith a lining 19 of suitable heat resisting material. forms no part of this divisionallapplication except as it is particularly related to the resistance element 11, no attempt will be made herein to describe in detail the heating unit, reference being made for this purpose to the above identiedvparent application Serial No. 436,897. lAngledbracket-rmembers 20 ofthe character shown mostclearly in Figure 2 are secured to the, threaded ends of the terminal.` members of the` heating unit. by means of l nuts 2,1, these angle .members being. so respectively secured in position that 'the branches 22 thereof. are arranged. in4 substantial; parallelism and KVbetween whichi'ssupported the resistanceelement 11.

Y As. appears most-clearly in Figures 3 and 4, thisre'sistance element-11 essentially comprises a tubular.. memberf'23. of refractory material about the external surface of which. the resistancegwire 24is spirally wound. Arranged at eitherend of thetubularmember 23 is a spool 25 cinch-conducting material and of a diameter greater vthan thatcf the tubular member 23. The lattermember andthe end spools 25 are maintained in assembledl relation by means of a metal tubev 2`6 the, opposite ends of which are respectively secured, as at 27, to the spools 25. This secure'ment lis preferably Yaccomplished by spinriingf ormot'herwise; forcing the ends of the met-alA ftube. 26 into vannular grooves respectively formed in thefspools 25. The space formed between the innerrefractory-tube23 and the outer metal tube 26is preferablylled .with insulating material 28.-

` vIn orderv to effectv the necessary electrical connection betweenthev endsof the resistance wire 24', and" theY angle brackets 20, which latter arelin' electrical'engagement with the termai elements of'therheater. unit, and. atene same timeafford asubs'tantial mechanical joint betweenthe, insulating tube 23 and .its supportingfend spools 25, thearrangements shown more particularly in Figures 3 and 5 are employed. In the form shown in Figure .3,endstuds .29 .are .emplyed,f these studs being each characterized by the provision offa threaded shank 30` and an enlarged headv 31 4of substantially yrectangular crosslsection, the spool 25 being provided in itsinnersurface. with. a rectangularly shaped socketfor partially vac commodating said rectangular head 31. The adjoining end of the tubular .member l 23` is diametrically slotted, as at `32,2*` for Anonrotatablyl receiving that portion off'thev stud head31. ywhich projects interiorly of theendspool. With the head 31 ofthe stud thuscommonly accommodatedwithin the socket portion lof` the-end spool and then-slotted portion of. theutubular member- 23,*.relative rotation between said spool and member is eiectually precluded. The head 31 ofthe/stud `is suitably reitured. @est .33. tefpermit .thefproieenon Inasmuch as the heating unit 1G therethrough of one end of the resistance wire 24, said wire being suitably brazed or otherwise permanently secured to said head to effect a positive electrical connection therebetween. The threaded shanks 30 of the studs extend through axial bores respectively provided in the end spools 25, therexteriorly projecting portions of these threaded Shanks 30 being adapted` for projection through suitable apertures formed in the lower ends of the branches 22 of the supporting brackets 2i). Nuts 34, threadedly engageable with the shanks 30, serve to maintain the resistance unit in the position shown most clearly in Figure 3.

Figures 5 and 6 show an alternative arrangement for preventing relative rotation between the tubular member 23 and the end spools 25.

vIn this modified construction studs 35 are employedwhich diier from the studs 29 o Figure 3 in that they are each provided with an axial extension 36 adapted for projection into. the bore of the tubular member.` 23'; This. axial extensiongis anchored within the end of the tube23. by means of a. tubular pin.- 37w=hich is projected.diametrically, through the tubefand extension. The enlarged rectangularly. shaped head 38v of the stud isnonfrotatably. positioned within the correspondingly shaped socketv 39 formed in the end spool such that: the inner surfaces of said head andspool aref-flushwith oneanother. The ends ofthe resistancerwire areV respectively threadedi through the tubular pins 37 and are secured'l thereto asby brazing, soldering or otherwise whereby a. permanent electrical connection is eiectedl between each endof the wire. andonevoi the-studs:35. In all other respects the resistance lunit ofthe form shown in Figure 5 is. similar` to-thatshownin FigurenB, both formsfbeing removably supported between the bracket members-20 in the lmanner appearing mostclearly in Figure-2. Y

It will thus be seen thattheoppositef-en of the resistance Wirearerespectively connected to theflterminal elementsvofi the heating-unit through the interventionvof the. end Astuds-and the;l supporting brackets.

It will be understood, ofcourse, that any suit# `able-means 'may be -providedto maintainy the heater unit in the operativeposition shown in Figure l.A It has Abeen found preferable', how ever, to employ a spring clamp-"40fvhavi'ng--a nat bodyorplate 41-which-is adapted to underlie `the base iange of the rail and aispringpressed pivoted member 42 adapted to overlie the inclined back plate 13 ofthe heater.` Thefuse of a spring clamp of the character just described eliminates the necessity of employing screws or bolts for securingv thel heater to the, rail at the same time that it greatlyfacilitates the ease with which the unit-'may be s'ecured'to and removed from-the rail; Should itl bede-fsi-red to remove theunitfroln'the railforpur poses of inspection, replacementor= repair yit is merelynecessary -to swing the baillmernber- 42 outwardly about its pivotedaxis whereupon the unit-may be bodily removed from-the ra-ILlno tools of any sort`I being 4recpiired Vinl'-thisope-raion.

Returning .againlto the resistance unit perv se, itnwill be observed that the;.end studs' thereof are longitudinally .bored,as= at v43,to. providea continuous f passage1 extendinge longitudinally through the resistance. unit; Thisl .passage .per-i mits. of a ..c.r.culationf;of;. fheated.. an. outwardly from the center of said unit to supplement the heat radiated from the external surface thereof.

It will be understood of course that the invention is susceptible of various changes and modications other than those hereinbefore pointed out, all without departing from the general principles or real spirit of the invention, and it is accordingly intended to claim the same broadly, as well as specifically, as indicated by the appended claims.

What is claimed as new and useful is:-

1. In an electric heater, a resistance unit therefor including a refractory tube upon the external surface of which a resistance wire is spirally wound, an end member of non-conducting material disposed adjacent one end of said tube, the inner surface of said member being provided with a recess of noncircular cross section, and a stud projecting axially through said member, said stud being provided with an enlarged intermediate portion of non-circular cross section adapted to be seated within said recess and with a tubular extension adapted to be projected within the bore of said refractory tube,

and means extending diametrically through said tube and tubular extension whereby to prevent relative rotation between said tube and end member.

2. In an electric heater, a resistance unit therefor including a refractory tube upon the external surface of which a resistance wire is spirally wound, an end member of non-conducting material disposed adjacent one end of said tube, the irmer surface of said member being provided with a recess of non-circular cross section, and a stud projecting axially through said member, said stud being provided with an enlarged intermediate portion of non-circular cross section adapted to be seated within said recess and with a tubular extension adapted to be projected within the bore of said refractory tube, and means extending diametrically through said tube and tubular extension whereby to prevent relative rotation between said tube and end member, said means being electrically connected to one end of the resistance wire.

WILLIAM H. GREENFIELD. 

